Epoxy resin-based composition for encapsulation of semiconductor devices

Abstract

The inorganic filler in the inventive epoxy resin-based composition is a combination of two kinds of quartz powder of which one is a quartz powder having a spherical particle form and the other is a pulverized quartz powder in a specified proportion. The resin composition is highly flowable and capable of giving encapsulation of semiconductor devices with little fins having outstandingly small thermal expansion coefficient and highly resistant against crack formation.

What is claimed is: 
     
       1. An epoxy resin-based composition for encapsulation of semiconductor devices which comprises: (a) 100 parts by weight of a phenol-curable epoxy resin; and   (b) from 100 to 500 parts by weight of a combination of silica fillers composed of (b-1) from 1 to 80% by weight of a quartz powder having a spherical particle form with an average particle diameter in the range from 1 to 25 μm, and   (b-2) from 20 to 99% by weight of a pulverized quartz powder with an average particle diameter in the range from 1 to 25 μm.     
     
     
       2. The epoxy resin-based composition as claimed in claim 1 wherein the pulverized quartz powder contains particles having a particle diameter larger than 20 μm in an amount not exceeding 10% by weight and particles having a particle diameter smaller than 1 μm in an amount not exceeding 15% by weight.